What is the center of the circle represented by this equation? (x - 7) 2 + (y + 4) 2 = 9?

The general form of a circle at center (h, k) and with radius r is:

(x - h) ² + (y - k) ² = r²

In your case, you can match your equation to:

(x - 7) ² + (y - (-4)) ² = 3²

So you have a circle centered at (7, - 4) with a radius of 3.